The temporal dynamics of medial and lateral frontal neural activity related to proactive cognitive control.

The neural correlates of proactive cognitive control were examined in two experiments using the counting Stroop task and a computerized Blackjack task in combination with event-related brain potentials (ERPs). The primary objective of the study was to determine whether slow wave activity related to proactive control would be observed in the two tasks. Consistent with the existing literature, transient components of the ERPs (i.e., medial frontal negativity and feedback related negativity) were observed over the medial frontal region in both tasks that were related to stimulus congruency and feedback processing, respectively. The medial frontal ERPs in both tasks were modeled with a pair of equivalent current dipoles placed along the anterior to posterior axis of the cingulate. Most importantly, slow wave activity was observed that differentiated incongruent trials from congruent trials after the response in the counting Stroop task, and losses from wins and ties in the Blackjack task. In the Blackjack task, a pair of dipoles in the left lateral frontal and posterior regions modeled the slow wave activity. These data reveal that updating goal representations that support proactive cognitive control may require several 100 ms in contrast to conflict or outcome monitoring that is associated with transient medial frontal neural activity.